#include <iostream>
using namespace std;

int main(int argc, char const *argv[])
{
    // n个人
    int n;
    cin >> n;

    int age[n];

    // 输入n个年龄
    for(int i=0; i<n; i++)
        cin >> age[i];

    // 求出平均年龄
    int sum = 0;
    for(int i=0; i<n; i++)
        sum += age[i];

    float averageAge = (float)sum/n;

    cout.precision(2);
    cout.setf(ios_base::fixed, ios_base::floatfield);
    cout << averageAge << endl;

    return 0;
}
